Free piston engine



w" il-1- Oct. 18, 1960 A. BRAUN FREE PISTON ENGINE Filed Feb. 7, 1958INVENTOR ATTORNEY United States Patent FREE Prs'roN ENGINE 7 AntonBraun, 437A Johnson St., Kingston, 2 i 2 Ontario, Canada Filed Feb. 1,1958, Set. No. 713,812

2 Claims. Cl. 123-46) This invention relates to internal combustionfreepiston engines. a

A general object of this invention is to provide a free piston engine ofmuch simplified overall design.

Another object is to provide a free piston engine, the

elements of which are simple and effective in design.

and operation, and which permits the convenient asso ciation therewithof an eflicient cooling system.

The invention will be described with reference to the accompanyingdrawing, in which The single figure is a longitudinal sectionalelevation of a free piston engine illustrating one embodiment of theinvention.

Referring to the drawing, the free piston engine therein illustratedincludes a centrally disposed compressor cylinder 90 which may alsoconstitute the main center frame of the engine. Fixed to one end ofcylinder 90 is an aligning disc 91 and to the other end thereof analigning disc 92.

A pair of engine cylinders 93 and 94 are mounted on disc 91, each suchcylinder extending outwardly therefrom and secured to disc 91 atopenings 95. A cylinder head 96 is mounted on the outer ends ofcylinders 93, 94 and provides a communicating passage 97. A fuelinjection nozzle 98 is mounted on the head 96 for injection of fuel intopassage 97.

Similarly, a pair of engine cylinders 99 and 100 are mounted on disc 92,each such cylinder extending outwardly therefrom and secured to disc 92at openings 101. A cylinder head 102 is mounted on the outer ends ofcylinders 99, 100 and provides a communicating passage 103. A fuelinjection nozzle 104 is mounted on head 102 for injection of fuel intopassage 103.

Mounted for reciprocation in compressor cylinder 90 are two compressorpistons 105 and 106. Piston 105 is provided with a plurality of openings107 controlled by valves 108 and piston 106 is provided with a pluralityof openings 109 controlled by valves 110, the arrangement being suchthat on inward movement of the pistons towards each other the valves 108and 110 are closed but on outward movement the valves open to providecommunication between the portions of cylinder 90 on the outer sides ofpistons 105 and 106 and the portion between such pistons. The outerportions of cylinder 90 and the outer sides of the pistons are open toatmosphere through respective series of openings 111 and 1 12 inaligning discs 91 and 92.

Mounted on piston 105 are a pair of engine pistons 113 and 114complementary to and reciprocating in engine cylinders 93 and 94.Pistons 113 and 114 are hollow, their inner ends being closed by a plate115, which forms a part of compressor piston 105. Openings 116 and 117in plate 115, with controlling valves 118 and 119, provide communicationbetween the interior of engine pistons 113 and 114 and the space betweencompressor pistons 105 and 106, such valves opening during a piston -113through ports 121, 122, thence through cyl- ICC a of; piston 113, ports120 are arranged to register with ports 121 in the cylinder 93. Ports121 communicate with a second series of ports 122 in cylinder 93 bymeansof an annular passage 123 provided by the ring 124. Thus,-air orgases may pass from the interior of inder 93, passage 97, and cylinder94, and is discharged through a series of ports 125 into an exhaust duct126.

. Engine piston 114 is of unported conventional type. It will beapparent that, in its innermost position, ports 125 are open but areclosed thereby during its initial outward motion.

Mounted on compressor piston 106 are a pair of engine pistons 127 and128 complementary to and reciprocating in engine cylinders 99 and 100.Pistons 127 and 128 and their associated elements are identical to andsymmetrical with pistons 113 and 114. The corresponding associatedelements include plate 129, openings 130 and 131 in the plate,controlling valves 132 and 133, ports 134, registering ports 135,communicating ports 136, passage 137, ring 138, exhaust ports 139, andexhaust duct 140.

In operation, after piston assemblies 105, 113, 114 and 106, 127, 128have reached their innermost position, as shown in the drawing,suflicient energy is stored up in the clearance space between them todrive them apart in order to elfect the engine compression stroke ofpistons 113, 114 and 127, 128. During this outward stroke, fresh airenters the space between compressor pistons 105, 106 through intakevalves 108, 110, the outer faces of such pistons being exposed toatmosphere. Outward motion of engine pistons 1'13, 114 and 127, 128closes ports 121, 122, 125 and 134, 135, 139 and compression occurs incylinders 93, 94 and passage 97 and cylinders 99, and passage 103. Oncompletion of the outward stroke, fuel is injected through nozzles 98,'104 and the piston assemblies are driven back to perform the compressorcompression and discharge stroke. When the air within the compressionchamber between pistons and 106 reach discharge pressure, it isdischarged through valves 118, 119 and 132, 133 into the interiors ofpistons 113, 114 and 127, 128. When the latter pistons uncover ports121, 122, and 134, 135, 139, the air flows through the paths previouslydescribed to eiiect scavenging, cooling and supercharging and theexhaust gases are discharged into exhaust ducts 126, 140.

It will be apparent that various changes may be made in the structuredescribed within the contemplation of the present invention. Forinstance, while but two engine pistons have been described as attachedto a common compressor piston (one acting as an intake piston and theother as an exhaust piston), it will be understood that any suitablenumber of engine pistons may be attached to each compressor piston. Thearrangement of engine pistons with respect to each compressor pistonshould, of course, be symmetrical. When more than one pair of enginepistons is attached to each compressor piston the engine could be run atfull load with, say, two pairs of engine pistons, for instance, twointake and two exhaust pistons on one common compressor piston. At acertain partial load point, one pair of engine pistons, for instance,one intake and one exhaust piston, could be shut off.

I claim:

1. An internal combustion free piston engine compris- Patented Oct. 18,1960 pressor pistons reciprocally mounted in said compressor cylinderand each having inner and outer faces, said compressor pistons providinga space between said inner faces thereof in said compressor cylinder, aplurality of engine cylinders extending outwardly from and secured toeach said aligning disc, a plurality of engine pistons carried by andextending outwardly from the outer face of each said compressor piston,each said engine piston having reciprocal engagement with one of saidengine cylinders, a plurality of air intake openings in each saidcompressor piston, a valve controlling each said air intake opening toclose said openings during the inward stroke of said compressor pistonsand to open saidopenings during the outward stroke of said compressorpistons for inlet of air into said space between said compressorpistons, each said engine piston being hollow and having at least oneopening communicating with said space, valve means controlling each saidengine piston opening to open said engine piston openings during theinward stroke of said compressor pistons and to close said engine pistonopenings during the outward stroke of said compressor pistons, at leastone of said engine pistons having air discharge ports, said enginecylinders having air discharge passages communicating with said airdischarge ports when said engine pistons are in the vicinity of theirinnermost positions.

2. An internal combustion free piston engine comprising a compressorcylinder having an aligning disc at each end thereof, each said aligningdisc having openings for passage of intake air to portions of theinterior of said compressor cylinder, a pair of opposed compressorpistons reciprocally mounted in said compressor cylinder and each havinginner and outer faces, said compressor pistons providinga space betweensaid inner faces thereof in said compressor cylinder, a plurality ofengine cylinders extending outwardly from and secured to each saidaligning disc, a cylinder head providing communication between the outerends of said engine cylinders, a plurality of engine pistons carried byand extending outwardly from the outer face of each said compressorpiston, each said engine piston having reciprocal engagement with one ofsaid engine cylinders, a plurality of air intake openings in each saidcompressor piston, a valve controlling each said air intake opening toclose said openings during the inward stroke of said compressor pistonsand to open said openings during the outward stroke of said compressorpistons for passage of intake air into said space between saidcompressor pistons, each said engine piston being hollow and having atleast one opening communicating with,

said space, valve means controlling each said engine piston opening toopen said engine piston openings during the inward stroke of saidcompressor pistons and to close said engine piston openings during theoutward stroke of said compressor pistons, at least one of said enginepistons and cylinders having registering air discharge ports when saidengine pistons are in the vicinity of their innermost positions, meansforming a passage leading from said registering air discharge ports tosaid engine cylinders, and gas discharge ducts leading from said enginecylinder.

References Cited in the file of this patent UNITED STATES PATENTS

